Like I mentioned in my first reply, I had 4:10's in my
LT1. I don't know how they will affect the LS1, though
I'm going to find out.
In my LT1 I still got 20 mpg with highway & city driving.
I did only use first gear at the track, I started in second
gear on the street. I had my rev limiter set to 6200 rpm
on the LT1 and shifted around 6000 / 6100. I never
got near the limiter going through the traps. Best trap
speed was 112. I think it was around 5800 rpm through
the trap if I remember correctly.